Pakistanis who continue to use 'Khuda hafiz' see the phrase as 'part of an ideological battle to retain what they see as a more pluralistic approach towards religion'. Photograph: M. SAJJAD/AP

Does it matter what name people use for God? This is the question thrown up as a result of a strange development in Pakistani etiquette.

Until about 10 years ago "Khuda hafiz", which means "God protect you", was the phrase commonly used to say goodbye. But, in the past decade, "Khuda hafiz" began to be overtaken by a new term "Allah hafiz". Now, "Allah hafiz" is used by everyone from religious clerics to fashion models and the country's top TV anchors.

While languages change and evolve with time, and Pakistan certainly has bigger problems such as corruption and militancy, the alteration has unsettled liberals in Pakistan, who say it reflects a wider change in the country's cultural landscape.

Khuda is the Urdu word for God, borrowed from Persian. Yet today, some people claim that Khuda can refer to any God, while Allah is the specific name for God in the Qur'anic scripture. Others have gone so far as to claim the word Khuda may even have pagan origins.

The promotion of "Allah hafiz" first began in the 1980s under the rule of General Zia-ul-Haq when Pakistan was involved in the US- and Saudi-backed jihad against the Soviet occupation of Afghanistan. According to some reports, "Allah hafiz" was first used in public in 1985 by a well-known TV host on the state-run PTV. However it would be years later that the greeting took off.

The arguments used by Muslims who are against using the name Khuda appear similar to the ones used by those Christians in the United States who say Allah is a different God to the one they worship. There is no denying there are key theological differences between Islam, Christianity and other religions when it comes to the nature of God, but these don't necessarily mean people from different faiths can't use the same name, while simultaneously holding on to their own unique beliefs.

A few years back, a Roman Catholic bishop from the Netherlands, Tiny Muskens, attracted media interest after calling on people of all faiths to use the name Allah for God: "Allah is a very beautiful word for God. Shouldn't we all say that from now on we will name God Allah? What does God care what we call him? It is our problem."

And millions of English-speaking Muslims have no hesitation in using the name God to refer to Allah. There are more than 10 million Christians who live in the Middle East who use Allah to refer to God. In Malaysia, there has been controversy on the matter for years about Christians being allowed to use Allah to refer to God, with even churches being attacked by some Muslims who object.

Some continue to use the "Khuda hafiz" despite the popularity of "Allah hafiz". To these people, "Khuda hafiz" is part of an ideological battle to retain what they see as a more pluralistic approach towards religion, yet for others it is tradition or nostalgia that keeps the usage alive. Outside Pakistan, "Khuda hafiz" is also known to be used in Iran, Afghanistan, Tajikistan and among Muslims in India.

Interestingly, while Allah is an Arabic word, the Arabs themselves don't use "Allah hafiz" – which is a purely Pakistani-manufactured invention mixing Arabic with Persian. Rather the Arabs use "ma salama" or "Allah ysalmak" when parting company. And for any who feel there is no need to mention God in a greeting in any language, remember even the English word "goodbye" derives from "God be with you", which was the standard greeting at one time.